In the past, copper interconnects on integrated circuits were not possible due to the diffusion of copper into the silicon substrate that changes the electrical properties of silicon in such a way as to prevent the transistors in the integrated circuits from functioning. Recent developments have proven successful in providing a diffusion barrier between the copper interconnect and the substrate. For example, IBM has developed a damascene process to deposit a diffusion barrier in silicon wafers along with copper. See IEEE Spectrum, January 1998, page 23 and IBM Research, Number 4, 1997, page 17. These developments for the first time allow for the commercial use of copper in integrated circuits.